Inserting third-party content items, such as advertisements, into a web page often requires knowledge of a number of web-page related technologies, such as HTML, CSS, Javascript, FTP file transfer, amongst others. At present, a web page designer can modify web page code of a web page to insert HTML and/or Javascript snippets into the existing web page code of a web page to create third party content slots through which ads can be displayed. Less tech-savvy web site owners lack the technical skills required to modify web page code and as such, are unable to insert third-party content slots within which third-party content items can appear along with primary content on a web page.